Printing-plate and process of making the same



UNITED STATES PATENT OFFICE.

WILLIAM H. STEELE, OF NEWVARK, NEW JERSEY.

PRINTING-PLATE AND PROCESS OF MAKING THE SAME.

SPECIFICATION forming part of Letters Patent No. 486,572, dated November22, 1892.

Application filed April 9, 1892. Serial No, 28,517. (No model.)

To aZZ whom it may concern.-

Be it known that I, WILLIAM H. STEELE, a citizen of the United States,residing at Newark,in the county of Essex and State of New Jersey, haveinvented certain new and useful Improvementsin Printing-Plates and theProcess of Making the Same; and I do hereby declare the following to bea full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same, reference being bad to the accompanying drawings, and toletters of reference marked thereon, which form a part of thisspecification.

The object of this invention is to produce printing-plates inquantities, such as may be transmitted through the mails at a reducedcost of postage, because of the small weight as compared with ordinarymetallic electroplates; to secure greater durability in such plates andperfection of outline in the imprint, and to secure other advantages andresults, some of which will be referred to in connection with thedescription of the method.

The invention consists in the improved printing-plate and the process ofmaking the same, all substantially as will be herein set forth, andfinally embraced in the claims.

I will now proceed to describe the method or process of preparing theplate. From a suitable original engraving or printing-plate which I mayterm a positive I take an im-. pression in a plastic compositionconsisting of clay,one-third,by weight shel1ac,one-third, and wood pulp,one-third, properly mixed. This is subjected to the action of the heatof live steam and forced through rollers to bring the ingredients intointimate union. After passing through the said rollers the compositionis in the form of sheets three-eighths of an inch in thickness, (more orless.) It is then put in an ordinary vulcanizer and is dried andhardened by steam heat or heat from steam-pipes, the said plateremaining in said vulcanizer about forty-eight hours, (more or less,)when it is sawed into suitable size and is ready to take the impressionabove referred to This is done by bringing the hardened composition intocontact, face to face, with the original or positive metallicprinting-plate after heating said metal-plate as high as possible bysteam heat and subjecting them to high pressure.

The design of the positive is thus negatively impressed into the face ofthe hardened composition. After removal from the press the compositionplate serves as a form or pattern to produce reproduction-positives toany desired extent or number. These reproductions are made in the samecomposition or plastic material as above referred to, differing only inthat the composition for the reproduction is not subjected to thepeculiar drying and hardening operation. I may, however, vary thecomposition for the reproductions; but in the case of the negatives ormatrices the composition described is preferred. By having the negativemuch harder than the reproduction there is no danger of the latteradhering to the formerwhen pressure is brought to bear, and as a resultthe said reproduction can be easily stripped from the negative withoutinjury to either.

Having thus described the invention, what I claim as new is 1. Theimproved printing-plate herein described, composed of clay, shellac, andwood pulp, and having on one of its faces the design of the imprintdesired, substantially as set forth.

2. The process of preparing printing-plates, which consists in taking animpression from a suitable original printing plate in a compositionconsisting of clay, shellac, and wood pulp subjected to a drying andhardening process, and taking from said hard impression a reproductionof the original in a composition of clay, shellac, and wood pulp nothardened to the degree of the hardened negative impression,substantially as set forth.

3. The process herein described of preparing printing-plates, whichconsists in taking a negative plate or matrix in a compositionconsisting of clay, shellac, and wood pulp, subjecting said compositionplate to a drying or hardening operation, and then taking from thehardened negative a positive or reproduction of the originalprinting-plate, substantiallyas set forth.

In testimony that I claim the foregoing I have hereunto set my hand this24th day of March, 1892.

WILLIAM H. STEELE. Witnesses:

CHARLES H. PELL, OSCAR A. MIcHnL.

